c3nav.mapdata.render.image → c3nav.mapdata.render
This commit is contained in:
Laura Klünder
parent
df451f9143
commit
36146ac954
8 changed files with 2 additions and 3 deletions
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@ -1,267 +0,0 @@
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import io
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import re
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import subprocess
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import zlib
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from itertools import chain
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from typing import Optional
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import numpy as np
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from django.conf import settings
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from django.core import checks
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from PIL import Image
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from shapely.affinity import translate
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from shapely.geometry import LineString, Polygon
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from shapely.ops import unary_union
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# import gobject-inspect, cairo and rsvg if the native rsvg SVG_RENDERER should be used
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from c3nav.mapdata.render.image.engines.base import FillAttribs, RenderEngine, StrokeAttribs
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if settings.SVG_RENDERER == 'rsvg':
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import pgi
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import cairocffi
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pgi.require_version('Rsvg', '2.0')
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from pgi.repository import Rsvg
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@checks.register()
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def check_svg_renderer(app_configs, **kwargs):
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errors = []
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if settings.SVG_RENDERER not in ('rsvg', 'rsvg-convert', 'inkscape'):
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errors.append(
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checks.Error(
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'Invalid SVG renderer: '+settings.SVG_RENDERER,
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obj='settings.SVG_RENDERER',
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id='c3nav.mapdata.E001',
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)
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)
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return errors
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class SVGEngine(RenderEngine):
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# draw an svg image. supports pseudo-3D shadow-rendering
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def __init__(self, *args, **kwargs):
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super().__init__(*args, **kwargs)
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# create base elements and counter for clip path ids
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self.g = ''
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self.defs = ''
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self.clip_path_i = 0
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# keep track which area of the image has which altitude currently
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self.altitudes = {}
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self.last_altitude = None
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# for fast numpy operations
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self.np_scale = np.array((self.scale, -self.scale))
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self.np_offset = np.array((-self.minx * self.scale, self.maxy * self.scale))
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# keep track of created blur filters to avoid duplicates
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self.blurs = set()
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self._create_geometry_cache = {}
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def get_xml(self, buffer=False):
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# get the root <svg> element as an ElementTree element, with or without buffer
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if buffer:
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width_px = self._trim_decimals(str(self.buffered_width))
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height_px = self._trim_decimals(str(self.buffered_height))
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offset_px = self._trim_decimals(str(-self.buffer))
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attribs = ' viewBox="' + ' '.join((offset_px, offset_px, width_px, height_px)) + '"' if buffer else ''
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else:
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width_px = self._trim_decimals(str(self.width))
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height_px = self._trim_decimals(str(self.height))
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attribs = ''
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result = ('<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" '
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'width="'+width_px+'" height="'+height_px+'"'+attribs+'>')
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if self.defs:
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result += '<defs>'+self.defs+'</defs>'
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if self.g:
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result += '<g>'+self.g+'</g>'
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result += '</svg>'
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return result
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def get_png(self):
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# render the image to png. returns bytes if f is None, otherwise it calls f.write()
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if self.width == 256 and self.height == 256 and not self.g:
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# create empty tile png with minimal size, indexed color palette with only one entry
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plte = b'PLTE' + bytearray(self.background_rgb)
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return (b'\x89PNG\r\n\x1a\n' +
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b'\x00\x00\x00\rIHDR\x00\x00\x01\x00\x00\x00\x01\x00\x01\x03\x00\x00\x00f\xbc:%\x00\x00\x00\x03' +
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plte + zlib.crc32(plte).to_bytes(4, byteorder='big') +
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b'\x00\x00\x00\x1fIDATh\xde\xed\xc1\x01\r\x00\x00\x00\xc2\xa0\xf7Om\x0e7\xa0\x00\x00\x00\x00\x00' +
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b'\x00\x00\x00\xbe\r!\x00\x00\x01\x7f\x19\x9c\xa7\x00\x00\x00\x00IEND\xaeB`\x82')
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if settings.SVG_RENDERER == 'rsvg':
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# create buffered surfaces
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buffered_surface = cairocffi.SVGSurface(None, self.buffered_width, self.buffered_height)
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buffered_context = cairocffi.Context(buffered_surface)
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# draw svg with rsvg
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handle = Rsvg.Handle()
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svg = handle.new_from_data(self.get_xml(buffer=True).encode())
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svg.render_cairo(buffered_context)
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# create cropped image
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surface = buffered_surface.create_similar(cairocffi.CONTENT_COLOR, self.width, self.height)
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context = cairocffi.Context(surface)
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# set background color
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context.set_source(cairocffi.SolidPattern(*(i/255 for i in self.background_rgb)))
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context.paint()
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# paste buffered immage with offset
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context.set_source_surface(buffered_surface, -self.buffer, -self.buffer)
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context.paint()
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return surface.write_to_png()
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elif settings.SVG_RENDERER == 'rsvg-convert':
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p = subprocess.run(('rsvg-convert', '-b', self.background, '--format', 'png'),
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input=self.get_xml(buffer=True).encode(), stdout=subprocess.PIPE, check=True)
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png = io.BytesIO(p.stdout)
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img = Image.open(png)
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img = img.crop((self.buffer, self.buffer,
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self.buffer + self.width,
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self.buffer + self.height))
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f = io.BytesIO()
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img.save(f, 'PNG')
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f.seek(0)
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return f.read()
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elif settings.SVG_RENDERER == 'inkscape':
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p = subprocess.run(('inkscape', '-z', '-b', self.background, '-e', '/dev/stderr', '/dev/stdin'),
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input=self.get_xml().encode(), stdout=subprocess.PIPE, stderr=subprocess.PIPE,
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check=True)
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png = p.stderr[p.stderr.index(b'\x89PNG'):]
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return png
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def _trim_decimals(self, data):
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# remove trailing zeros from a decimal – yes this is slow, but it greatly speeds up cairo rendering
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return re.sub(r'([0-9]+)((\.[1-9])[0-9]+|\.[0-9]+)?', r'\1\2', data)
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def _geometry_to_svg(self, geom):
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# scale and move geometry and create svg code for it
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if isinstance(geom, Polygon):
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return ('<path d="' +
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' '.join((('M %.1f %.1f L'+(' %.1f %.1f'*(len(ring.coords)-1))+' z') %
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tuple((np.array(ring)*self.np_scale+self.np_offset).flatten()))
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for ring in chain((geom.exterior,), geom.interiors))
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+ '"/>').replace('.0 ', ' ')
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if isinstance(geom, LineString):
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return (('<path d="M %.1f %.1f L'+(' %.1f %.1f'*(len(geom.coords)-1))+'"/>') %
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tuple((np.array(geom)*self.np_scale+self.np_offset).flatten())).replace('.0 ', ' ')
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try:
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geoms = geom.geoms
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except AttributeError:
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return ''
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return ''.join(self._geometry_to_svg(g) for g in geoms)
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def _create_geometry(self, geometry, attribs='', tag='g', cache_key=None):
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# convert a shapely geometry into an svg xml element
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result = None
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if cache_key is not None:
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result = self._create_geometry_cache.get(cache_key, None)
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if result is None:
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result = self._geometry_to_svg(geometry)
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if cache_key is not None:
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self._create_geometry_cache[cache_key] = result
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return '<'+tag+attribs+'>'+result+'</'+tag+'>'
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def register_clip_path(self, geometry):
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defid = 'clip'+str(self.clip_path_i)
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self.defs += self._create_geometry(geometry, ' id="'+defid+'"', tag='clipPath')
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self.clip_path_i += 1
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return defid
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def add_shadow(self, geometry, elevation, clip_path=None):
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# add a shadow for the given geometry with the given elevation and, optionally, a clip path
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elevation = float(min(elevation, 2))
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blur_radius = elevation / 3 * 0.25
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shadow_geom = translate(geometry.buffer(blur_radius),
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xoff=(elevation / 3 * 0.12), yoff=-(elevation / 3 * 0.12))
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if clip_path is not None:
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if shadow_geom.distance(clip_path) >= blur_radius:
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return
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blur_id = 'blur'+str(int(elevation*100))
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if elevation not in self.blurs:
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self.defs += ('<filter id="'+blur_id+'" width="200%" height="200%" x="-50%" y="-50%">'
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'<feGaussianBlur stdDeviation="'+str(blur_radius * self.scale)+'"/>'
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'</filter>')
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self.blurs.add(elevation)
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attribs = ' filter="url(#'+blur_id+')" fill="#000" fill-opacity="0.2"'
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if clip_path:
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attribs += ' clip-path="url(#'+self.register_clip_path(clip_path)+')"'
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shadow = self._create_geometry(shadow_geom, attribs)
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self.g += shadow
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def clip_altitudes(self, new_geometry, new_altitude=None):
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# registrer new geometry with specific (or no) altitude
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# a geometry with no altitude will reset the altitude information of its area as if nothing was ever there
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for altitude, geometry in tuple(self.altitudes.items()):
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if altitude != new_altitude:
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self.altitudes[altitude] = geometry.difference(new_geometry)
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if self.altitudes[altitude].is_empty:
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self.altitudes.pop(altitude)
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if new_altitude is not None:
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if self.last_altitude is not None and self.last_altitude > new_altitude:
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raise ValueError('Altitudes have to be ascending.')
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self.last_altitude = new_altitude
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if new_altitude in self.altitudes:
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self.altitudes[new_altitude] = unary_union([self.altitudes[new_altitude], new_geometry])
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else:
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self.altitudes[new_altitude] = new_geometry
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def _add_geometry(self, geometry, fill: Optional[FillAttribs] = None, stroke: Optional[StrokeAttribs] = None,
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filter=None, clip_path=None, altitude=None, elevation=None, shape_cache_key=None):
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if fill:
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attribs = ' fill="'+(fill.color)+'"'
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if fill.opacity:
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attribs += ' fill-opacity="'+str(fill.opacity)[:4]+'"'
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else:
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attribs = ' fill="none"'
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if stroke:
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width = stroke.width*self.scale
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if stroke.min_px:
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width = max(width, stroke.min_px)
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attribs += ' stroke-width="' + self._trim_decimals(str(width)) + '" stroke="' + stroke.color + '"'
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if stroke.opacity:
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attribs += ' stroke-opacity="'+str(stroke.opacity)[:4]+'"'
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if filter:
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attribs += ' filter="url(#'+filter+')"'
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if clip_path:
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attribs += ' clip-path="url(#'+clip_path+')"'
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if geometry is not None:
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if False:
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# old shadow rendering. currently needs too much resources
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if altitude is not None or elevation is not None:
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if elevation is not None:
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if elevation:
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self.add_shadow(geometry, elevation)
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else:
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for other_altitude, other_geom in self.altitudes.items():
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self.add_shadow(geometry, altitude-other_altitude, clip_path=other_geom)
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self.clip_altitudes(geometry, altitude)
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else:
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if elevation is not None:
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self.add_shadow(geometry, elevation)
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element = self._create_geometry(geometry, attribs, cache_key=shape_cache_key)
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else:
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element = '<rect width="100%" height="100%"'+attribs+'>'
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self.g += element
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return element
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